import {
  document,
	window,
	HTMLCanvasElement,
	requestAnimationFrame,
	cancelAnimationFrame,
core,
	Event,
  Event0
} from "dhtml-weixin"
import * as THREE from './three/Three';

import Stats from 'three/addons/libs/stats.module.js';

import { OBJLoader } from 'three/addons/loaders/OBJLoader.js';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
import { OrbitControls0 } from 'three/addons/controls/OrbitControls0.js';
import { GodRaysFakeSunShader, GodRaysDepthMaskShader, GodRaysCombineShader, GodRaysGenerateShader } from 'three/addons/shaders/GodRaysShader.js';

var requestId
Page({
  onShareAppMessage(){
    return getApp().onShare()
  },
  onShareTimeline(){
     return {title:"ThreeX 2.0"}
  },
	onUnload() {
		cancelAnimationFrame(requestId, this.canvas)
		this.worker && this.worker.terminate()
if(this.canvas) this.canvas = null
		setTimeout(() => {
			if (this.renderer instanceof THREE.WebGLRenderer) {
				this.renderer.dispose()
				this.renderer.forceContextLoss()
				this.renderer.context = null
				this.renderer.domElement = null
				this.renderer = null
			}
		}, 0)
	},
  webgl_touch(e){
		const web_e = (window.platform=="devtools"?Event:Event0).fix(e)
		this.canvas.dispatchEvent(web_e)
  },
  onLoad() {
		document.createElementAsync("canvas", "webgl2").then(canvas => {
      this.canvas = canvas
      this.body_load(canvas).then()
    })
  },
  async body_load(canvas3d) {	
  let container, stats;
  let camera, scene, renderer, materialDepth;

  let sphereMesh;

  const sunPosition = new THREE.Vector3( 0, 1000, - 1000 );
  const clipPosition = new THREE.Vector4();
  const screenSpacePosition = new THREE.Vector3();

  const postprocessing = { enabled: true };

  const orbitRadius = 200;

  const bgColor = 0x000511;
  const sunColor = 0xffee00;

  // Use a smaller size for some of the god-ray render targets for better performance.
  const godrayRenderTargetResolutionMultiplier = 1.0 / 4.0;

  init();
  animate();

  function init() {

    container = document.createElement( 'div' );
    document.body.appendChild( container );

    //

    camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 1, 3000 );
    camera.position.z = 200;

    scene = new THREE.Scene();

    //

    materialDepth = new THREE.MeshDepthMaterial();

    // tree

    const loader = new OBJLoader();
    loader.load( 'models/obj/tree.obj', function ( object ) {

      object.position.set( 0, - 150, - 150 );
      object.scale.multiplyScalar( 400 );
      scene.add( object );

    } );

    // sphere

    const geo = new THREE.SphereGeometry( 1, 20, 10 );
    sphereMesh = new THREE.Mesh( geo, new THREE.MeshBasicMaterial( { color: 0x000000 } ) );
    sphereMesh.scale.multiplyScalar( 20 );
    scene.add( sphereMesh );

    //

    renderer = new THREE.WebGLRenderer();
    renderer.setClearColor( 0xffffff );
    renderer.setPixelRatio( window.devicePixelRatio );
    renderer.setSize( window.innerWidth, window.innerHeight );
    container.appendChild( renderer.domElement );

    renderer.autoClear = false;

    const controls = new (window.platform=="devtools"?OrbitControls:OrbitControls0)( camera, renderer.domElement );
    controls.minDistance = 50;
    controls.maxDistance = 500;

    //

    stats = new Stats();
    container.appendChild( stats.dom );

    //

    window.addEventListener( 'resize', onWindowResize );

    //

    initPostprocessing( window.innerWidth, window.innerHeight );

  }

  //

  function onWindowResize() {

    const renderTargetWidth = window.innerWidth;
    const renderTargetHeight = window.innerHeight;

    camera.aspect = renderTargetWidth / renderTargetHeight;
    camera.updateProjectionMatrix();

    renderer.setSize( renderTargetWidth, renderTargetHeight );
    postprocessing.rtTextureColors.setSize( renderTargetWidth, renderTargetHeight );
    postprocessing.rtTextureDepth.setSize( renderTargetWidth, renderTargetHeight );
    postprocessing.rtTextureDepthMask.setSize( renderTargetWidth, renderTargetHeight );

    const adjustedWidth = renderTargetWidth * godrayRenderTargetResolutionMultiplier;
    const adjustedHeight = renderTargetHeight * godrayRenderTargetResolutionMultiplier;
    postprocessing.rtTextureGodRays1.setSize( adjustedWidth, adjustedHeight );
    postprocessing.rtTextureGodRays2.setSize( adjustedWidth, adjustedHeight );

  }

  function initPostprocessing( renderTargetWidth, renderTargetHeight ) {

    postprocessing.scene = new THREE.Scene();

    postprocessing.camera = new THREE.OrthographicCamera( - 0.5, 0.5, 0.5, - 0.5, - 10000, 10000 );
    postprocessing.camera.position.z = 100;

    postprocessing.scene.add( postprocessing.camera );

    postprocessing.rtTextureColors = new THREE.WebGLRenderTarget( renderTargetWidth, renderTargetHeight, { type: THREE.HalfFloatType } );

    // Switching the depth formats to luminance from rgb doesn't seem to work. I didn't
    // investigate further for now.
    // pars.format = LuminanceFormat;

    // I would have this quarter size and use it as one of the ping-pong render
    // targets but the aliasing causes some temporal flickering

    postprocessing.rtTextureDepth = new THREE.WebGLRenderTarget( renderTargetWidth, renderTargetHeight, { type: THREE.HalfFloatType } );
    postprocessing.rtTextureDepthMask = new THREE.WebGLRenderTarget( renderTargetWidth, renderTargetHeight, { type: THREE.HalfFloatType } );

    // The ping-pong render targets can use an adjusted resolution to minimize cost

    const adjustedWidth = renderTargetWidth * godrayRenderTargetResolutionMultiplier;
    const adjustedHeight = renderTargetHeight * godrayRenderTargetResolutionMultiplier;
    postprocessing.rtTextureGodRays1 = new THREE.WebGLRenderTarget( adjustedWidth, adjustedHeight, { type: THREE.HalfFloatType } );
    postprocessing.rtTextureGodRays2 = new THREE.WebGLRenderTarget( adjustedWidth, adjustedHeight, { type: THREE.HalfFloatType } );

    // god-ray shaders

    const godraysMaskShader = GodRaysDepthMaskShader;
    postprocessing.godrayMaskUniforms = THREE.UniformsUtils.clone( godraysMaskShader.uniforms );
    postprocessing.materialGodraysDepthMask = new THREE.ShaderMaterial( {

      uniforms: postprocessing.godrayMaskUniforms,
      vertexShader: godraysMaskShader.vertexShader,
      fragmentShader: godraysMaskShader.fragmentShader

    } );

    const godraysGenShader = GodRaysGenerateShader;
    postprocessing.godrayGenUniforms = THREE.UniformsUtils.clone( godraysGenShader.uniforms );
    postprocessing.materialGodraysGenerate = new THREE.ShaderMaterial( {

      uniforms: postprocessing.godrayGenUniforms,
      vertexShader: godraysGenShader.vertexShader,
      fragmentShader: godraysGenShader.fragmentShader

    } );

    const godraysCombineShader = GodRaysCombineShader;
    postprocessing.godrayCombineUniforms = THREE.UniformsUtils.clone( godraysCombineShader.uniforms );
    postprocessing.materialGodraysCombine = new THREE.ShaderMaterial( {

      uniforms: postprocessing.godrayCombineUniforms,
      vertexShader: godraysCombineShader.vertexShader,
      fragmentShader: godraysCombineShader.fragmentShader

    } );

    const godraysFakeSunShader = GodRaysFakeSunShader;
    postprocessing.godraysFakeSunUniforms = THREE.UniformsUtils.clone( godraysFakeSunShader.uniforms );
    postprocessing.materialGodraysFakeSun = new THREE.ShaderMaterial( {

      uniforms: postprocessing.godraysFakeSunUniforms,
      vertexShader: godraysFakeSunShader.vertexShader,
      fragmentShader: godraysFakeSunShader.fragmentShader

    } );

    postprocessing.godraysFakeSunUniforms.bgColor.value.setHex( bgColor );
    postprocessing.godraysFakeSunUniforms.sunColor.value.setHex( sunColor );

    postprocessing.godrayCombineUniforms.fGodRayIntensity.value = 0.75;

    postprocessing.quad = new THREE.Mesh(
      new THREE.PlaneGeometry( 1.0, 1.0 ),
      postprocessing.materialGodraysGenerate
    );
    postprocessing.quad.position.z = - 9900;
    postprocessing.scene.add( postprocessing.quad );

  }

  function animate() {

    requestId = requestAnimationFrame( animate );

    stats.begin();
    render();
    stats.end();

  }

  function getStepSize( filterLen, tapsPerPass, pass ) {

    return filterLen * Math.pow( tapsPerPass, - pass );

  }

  function filterGodRays( inputTex, renderTarget, stepSize ) {

    postprocessing.scene.overrideMaterial = postprocessing.materialGodraysGenerate;

    postprocessing.godrayGenUniforms[ 'fStepSize' ].value = stepSize;
    postprocessing.godrayGenUniforms[ 'tInput' ].value = inputTex;

    renderer.setRenderTarget( renderTarget );
    renderer.render( postprocessing.scene, postprocessing.camera );
    postprocessing.scene.overrideMaterial = null;

  }

  function render() {

    const time = Date.now() / 4000;

    sphereMesh.position.x = orbitRadius * Math.cos( time );
    sphereMesh.position.z = orbitRadius * Math.sin( time ) - 100;

    if ( postprocessing.enabled ) {

      clipPosition.x = sunPosition.x;
      clipPosition.y = sunPosition.y;
      clipPosition.z = sunPosition.z;
      clipPosition.w = 1;

      clipPosition.applyMatrix4( camera.matrixWorldInverse ).applyMatrix4( camera.projectionMatrix );

      // perspective divide (produce NDC space)

      clipPosition.x /= clipPosition.w;
      clipPosition.y /= clipPosition.w;

      screenSpacePosition.x = ( clipPosition.x + 1 ) / 2; // transform from [-1,1] to [0,1]
      screenSpacePosition.y = ( clipPosition.y + 1 ) / 2; // transform from [-1,1] to [0,1]
      screenSpacePosition.z = clipPosition.z; // needs to stay in clip space for visibilty checks

      // Give it to the god-ray and sun shaders

      postprocessing.godrayGenUniforms[ 'vSunPositionScreenSpace' ].value.copy( screenSpacePosition );
      postprocessing.godraysFakeSunUniforms[ 'vSunPositionScreenSpace' ].value.copy( screenSpacePosition );

      // -- Draw sky and sun --

      // Clear colors and depths, will clear to sky color

      renderer.setRenderTarget( postprocessing.rtTextureColors );
      renderer.clear( true, true, false );

      // Sun render. Runs a shader that gives a brightness based on the screen
      // space distance to the sun. Not very efficient, so i make a scissor
      // rectangle around the suns position to avoid rendering surrounding pixels.

      const sunsqH = 0.74 * window.innerHeight; // 0.74 depends on extent of sun from shader
      const sunsqW = 0.74 * window.innerHeight; // both depend on height because sun is aspect-corrected

      screenSpacePosition.x *= window.innerWidth;
      screenSpacePosition.y *= window.innerHeight;

      renderer.setScissor( screenSpacePosition.x - sunsqW / 2, screenSpacePosition.y - sunsqH / 2, sunsqW, sunsqH );
      renderer.setScissorTest( true );

      postprocessing.godraysFakeSunUniforms[ 'fAspect' ].value = window.innerWidth / window.innerHeight;

      postprocessing.scene.overrideMaterial = postprocessing.materialGodraysFakeSun;
      renderer.setRenderTarget( postprocessing.rtTextureColors );
      renderer.render( postprocessing.scene, postprocessing.camera );

      renderer.setScissorTest( false );

      // -- Draw scene objects --

      // Colors

      scene.overrideMaterial = null;
      renderer.setRenderTarget( postprocessing.rtTextureColors );
      renderer.render( scene, camera );

      // Depth

      scene.overrideMaterial = materialDepth;
      renderer.setRenderTarget( postprocessing.rtTextureDepth );
      renderer.clear();
      renderer.render( scene, camera );

      //

      postprocessing.godrayMaskUniforms[ 'tInput' ].value = postprocessing.rtTextureDepth.texture;

      postprocessing.scene.overrideMaterial = postprocessing.materialGodraysDepthMask;
      renderer.setRenderTarget( postprocessing.rtTextureDepthMask );
      renderer.render( postprocessing.scene, postprocessing.camera );

      // -- Render god-rays --

      // Maximum length of god-rays (in texture space [0,1]X[0,1])

      const filterLen = 1.0;

      // Samples taken by filter

      const TAPS_PER_PASS = 6.0;

      // Pass order could equivalently be 3,2,1 (instead of 1,2,3), which
      // would start with a small filter support and grow to large. however
      // the large-to-small order produces less objectionable aliasing artifacts that
      // appear as a glimmer along the length of the beams

      // pass 1 - render into first ping-pong target
      filterGodRays( postprocessing.rtTextureDepthMask.texture, postprocessing.rtTextureGodRays2, getStepSize( filterLen, TAPS_PER_PASS, 1.0 ) );

      // pass 2 - render into second ping-pong target
      filterGodRays( postprocessing.rtTextureGodRays2.texture, postprocessing.rtTextureGodRays1, getStepSize( filterLen, TAPS_PER_PASS, 2.0 ) );

      // pass 3 - 1st RT
      filterGodRays( postprocessing.rtTextureGodRays1.texture, postprocessing.rtTextureGodRays2, getStepSize( filterLen, TAPS_PER_PASS, 3.0 ) );

      // final pass - composite god-rays onto colors

      postprocessing.godrayCombineUniforms[ 'tColors' ].value = postprocessing.rtTextureColors.texture;
      postprocessing.godrayCombineUniforms[ 'tGodRays' ].value = postprocessing.rtTextureGodRays2.texture;

      postprocessing.scene.overrideMaterial = postprocessing.materialGodraysCombine;

      renderer.setRenderTarget( null );
      renderer.render( postprocessing.scene, postprocessing.camera );
      postprocessing.scene.overrideMaterial = null;

    } else {

      renderer.setRenderTarget( null );
      renderer.clear();
      renderer.render( scene, camera );

    }

  }

  }
})